It took some guessing since there were several pipes of the same color going through the slab but I was able to isolate it.
I ended up cutting the pipe and putting in a plug to stop the leak so I can continue work on it next week to fix it properly.
After plugging up, my observation is that it leads to the downstairs bathroom as the downstairs bathroom no longer has hot water.
I will update this post as I move forward with the fix.